Efficient elevated temperature hydrogen direct purification and separation technology

Abstract

Hydrogen, essential as a clean energy carrier and chemical feedstock, demands purification processes that are both efficient and economical. This study presents an analysis of the elevated temperature hydrogen direct purification and separation (HDPS) technology, an innovative method for achieving high hydrogen recovery rates. The LaNi₄Al alloy, utilized as an absorbent, operates effectively at elevated temperatures and exhibits resilience against impurities. The HDPS process is strategically designed, incorporating pressurization, absorption, co-current blowdown at varied rates, and vacuum desorption, and is distinguished from conventional pressure swing adsorption (PSA) based on theoretical insights into their operational differences and similarities. Integrated with a methanol reforming module, a temperature swing adsorption (TSA) module, and a proton exchange membrane fuel cell (PEMFC), the pilot-scale HDPS system outperforms traditional PSA methods in efficiency. The HDPS-TSA process achieves excellent hydrogen recovery rates (91.28%) and purities (99.999%), satisfying the stringent requirements of fuel cells. The HDPS-TSA system's electricity consumption and heat demand are comparable to or lower than those of traditional vacuum pressure swing adsorption (VPSA) and TSA processes, positioning it as a promising solution for sustainable hydrogen production systems.